1. Field of the Invention
The present invention relates to ship inspecting devices and, more particularly, to devices for inspecting interior surfaces surrounding and defining a ship's hold.
2. Description of the Related Art
Ships having holds to receive liquid, such as oil, or bulk material, such as grain or sand, must be periodically inspected to insure that the welds joining the sheet metal of the hold to the supporting steel beams have not deteriorated due to the stresses encountered during transport.
Several methods are presently employed to inspect the bottom wall, vertical side walls, transverse webs, and the underdeck surface that define the ship's hold. One method presently employed to inspect the bottom wall, side walls and transverse webs requires the inspector to walk within the empty hold to inspect the bottom wall and a lower portion of the side walls, transverse webs, and the welds associated therewith. Thereafter, the hold is incrementally flooded to allow the inspector, then located in a small boat, to float within the hold and inspect the welds on the side walls and transverse webs which are vertically remote from the bottom wall. At the end of the flooding process, the inspector is close to the underdeck surface and can inspect the welds thereon, as well as the welds joining the underdeck to the side walls or transverse webs. This type of inspection process is undesirable as it is very time consuming to incrementally flood each hold for individual inspection of thereof, and increases the inspection time and, hence, the period for which the ship is unavailable for use.
Another method of inspecting the underdeck surface requires the inspector to manually hang and swing from beams provided by the underdeck and to view the underdeck welds while so suspended. It is obvious that such an inspection procedure is quite dangerous and has, in fact, resulted in several deaths. As such, this method of underdeck inspection is generally considered undesirable.
The inaccessibility of the underdeck surface has resulted in it generally going uninspected, which is not desirable from a safety standpoint since any degradation of the ship's strength resulting from breaks or discontinuities in the underdeck welds go undetected, and therefore increases the chance and extent of structural damage to the ship when under great stress, such as during a storm or when the ship has run aground.
Therefore, there exists a need in the art for a method and an apparatus for inspecting the underdeck of a ship and for inspecting the union of the underdeck with the vertical side walls and transverse webs.